The present invention relates generally to packages for fresh red meat. Particularly, this invention is directed to the packaging of food products such that the packaged product may be maintained in one condition under certain circumstances and then converted to another condition. Specifically, packages in accordance with the present invention provide for distribution of a packaged product in a low oxygen environment and for introduction of oxygen to the product surface at a supermarket or other retail outlet. Such introduction of oxygen is achieved either by permeation of oxygen through a film in contact with the product surface or through an exchange with a low oxygen gaseous atmosphere contained around the product.
While a wide variety of food products can be packaged in accordance with the teachings of this invention, it is particularly advantageous in connection with the packaging of fresh red meat such that the meat may be transported in a low oxygen atmosphere, that is, preferably 0.5% O.sub.2 or less, most preferably 0.05% O.sub.2 or less, and then caused to bloom when it reaches a supermarket by exposure to oxygen.
Historically, large sub-primal cuts of meat have been butchered and packaged in each supermarket. This, however, can be somewhat inefficient and result in certain undesirable additional costs. For example, all cuts from a large sub-primal must be sold at once. Instead it would be preferable to permit the meat to be butchered and packaged at a central facility which benefits from economies of scale and thereafter shipped to individual supermarkets to be merchandised one retail cut at a time.
In the past, the goal of central fresh red meat processing has not been achievable because most consumers prefer to buy meat which is reddened in color as a result of exposure to oxygen. However, the meat maintains its reddened color for approximately one to three days and, thereafter, turns a brown color which is undesirable to most consumers. In an effort to maintain a reddened color, cuts of fresh red meat have been centrally packaged in high oxygen atmosphere packages. However, meat contained in such packages typically turns brown in ten to twelve days.
Therefore, if the meat was butchered and packaged in a gas permeable (hereinafter "permeable") film, as is typical at retail, at a central location and then shipped to another location for eventual sale, in all likelihood, by the time the package reached the retail outlet the meat would have undergone the transformation to the brown color and would be effectively unsalable. Conversely, if the meat was butchered and packaged at a central location in a gas-impermeable (hereinafter "impermeable") film, either under vacuum or with vacuum and a low oxygen gas flush, and then shipped to another location for eventual sale, the meat would reach the retail outlet having a purple color which is typical of meat prior to exposure to oxygen. Heretofore, marketing efforts to teach the consumer about the harmlessness of the purple color have proved to be difficult. And, if the gas impermeable film was a component of a conventional package having a tray which is overwrapped or lidded with a film and which contains a low oxygen atmosphere, the impermeable film would have to be removed and replaced with a permeable film in order to allow for bloom of the meat to a bright red color prior to display for the consumer, negating to a large extent the benefits of a central processing facility.
A variety of packages have been developed in an effort to provide a means for transporting meat in a low oxygen environment and for quickly and easily introducing oxygen to the meat at the retail outlet immediately prior to display to the consumer.
One approach to solving this problem has involved the development of peelable films. That is, films have been developed which readily delaminate into permeable and impermeable portions. Such a film is sealed to a support member, such as a tray, which contains the meat product, thereby forming a gas impermeable package for distribution. At the retail outlet, the gas impermeable portions are peeled from the film leaving a permeable film sealed to the tray and, therefore, a gas permeable package which allows the meat to bloom to bright red because of the exchange with atmospheric oxygen.
The peelable film may extend over the contained product and be sealed to the periphery of the tray as a lid or it may be heated and draped over the product under vacuum to form to a vacuum skin package. The permeable portion of the peelable film generally has a much higher gas transmission rate than that of the entire film prior to delamination, e.g., 5,000 to 25,000 cc/m.sup.2 /24 hrs./atm. at 73.degree. F. as compared to 0 to 50 cc/m.sup.2 /24 hrs./atm. at 73.degree. F. prior to delamination.
Most of the other approaches to achieving the goal of central fresh red meat processing have involved the development of a variety of dual web packages of the type having a permeable film covering the meat product and an impermeable film, which is removed at the retail outlet, covering the permeable film wherein the permeable film and the impermeable film are separate, discreet films.
Examples of these types of packages include dual overwrap packages wherein a permeable film is wrapped around the meat and its support member and an impermeable film is wrapped about the permeable film; dual lid packages which include a permeable lid and an impermeable lid sealed to the periphery of the support member; and packages with a head space which allows for the introduction of a treating gas, typically nitrogen, carbon dioxide or some mixture of the two, between a permeable film adjacent to the meat product and an impermeable upper web. Typical gas transmission rates for the gas permeable films in such dual web packages range from about 5,000 to 25,000 cc/m.sup.2 /24 hrs./atm. at 73.degree. F.
Unfortunately, for dual web or peelable film packages as discussed above, any information such as weight and pricing contained on a label affixed to the permeable web following removal of the impermeable web must currently be procured at the retail facility. That is, central labeling for dual web packages has not been feasible because the packaging machinery typically applies the permeable film and the impermeable film simultaneously. Applying the permeable film, stopping to weigh the package, and applying an individualized label to the permeable film prior to applying the impermeable film would significantly increase packaging costs. For peelable films where the permeable web and impermeable web are coextruded, interjection of a label between the two webs would be impossible. Labels applied to the side walls or bottom surface of the support tray are not attractive to consumers who are accustomed to labeling on the upper surface of products. Thus, while packages of the type discussed above have obviated the need for in-store butchering, retail workers are still required to weigh each individual package and to create a unique label for each package.
Thus, it is an object of the present invention to provide a package which allows for central processing of fresh red meat with minimal processing required at retail.
It is yet another object of the present invention to provide a package which is similar in appearance to that which consumers are accustomed to seeing for meat packaging.
It is yet another object of the present invention to provide a package which may be assembled, filled, sealed, weighed and labeled at a central processing facility on conventional equipment.